An active driving type liquid crystal apparatus which is an electro-optical apparatus has pixels which modulate light, a semiconductor circuit (a scan line driving circuit, a data line driving circuit, and the like) which drives the pixels, and the like. In the liquid crystal apparatus, there is a concern that transistors which configure pixels, semiconductor circuits, or the like will suffer irreparable electrostatic damage due to static electricity and electrostatic countermeasures which suppress the influence of static electricity are important. For example, PTL 1 proposes a liquid crystal apparatus which is provided with an electrostatic protection circuit (a static electricity protection circuit).
FIG. 16 is a circuit diagram of the static electricity protection circuit described in PTL 1. As shown in FIG. 16, a static electricity protection circuit 500 described in PTL 1 has a p-type transistor 504 and an n-type transistor 505. The source and gate of the p-type transistor 504 are connected with a high potential wiring 502 and a potential VH is supplied thereto. The source and gate of the n-type transistor 505 are connected with a low potential wiring 503 and a potential VL which is a lower potential than the potential VH is supplied thereto. The drain of the p-type transistor 504 and the drain of the n-type transistor 505 are connected with a signal wiring 501.
In a case where the potential of the signal wiring 501 is in a range of VL to VH, the p-type transistor 504 and the n-type transistor 505 are in an OFF state and the liquid crystal apparatus operates normally without electrical interference from the signal wiring 501, the high potential wiring 502, or the low potential wiring 503. When the potential of the signal wiring 501 is outside of the range of VL to VH due to static electricity, one of the p-type transistor 504 and the n-type transistor 505 is in an ON state (a conductive state). For example, when the potential of the signal wiring 501 is greater than VH due to static electricity, the p-type transistor 504 is in the ON state. When the potential of the signal wiring 501 is lower than VL due to static electricity, the n-type transistor 505 is in the ON state. In this manner, when the potential of the signal wiring 501 changes due to static electricity, one of the high potential wiring 502 and the low potential wiring 503 is in a conductive state and so is the signal wiring 501. Then, an electrical charge which is applied to the signal wiring 501 due to static electricity is distributed (discharged) to whichever one of the high potential wiring 502 or the low potential wiring 503 is in the conductive state and the changes in the potential of the signal wiring 501 due to static electricity are reduced. Since changes in the potential of the signal wiring 501 due to static electricity are reduced, it is difficult for the semiconductor circuit which is connected with the signal wiring 501 to suffer irreparable electrostatic damage (for example, electrostatic breakdown).